Blast furnace raw material charging method

Abstract

This invention provides a method for charging raw materials into a blast furnace, achieving a suitable particle size distribution of raw materials in the top hopper for both forward and reverse tilting charging. This increases the gas flow rate near the center of the blast furnace regardless of the tilting method, further improving ventilation and reduction efficiency. A structure of a predetermined shape is installed within the raw material storage section of the top hopper. The position of the raw material collision with this structure during the storage process is determined based on the tilting method during the charging process.

Description

Technical Field

[0001] This invention relates to a method for charging raw materials into a blast furnace. Background Technology

[0002] In a blast furnace, typically as follows Figure 1 The process involves the following: ore raw materials such as sintered ore, pellets, and lump ore are alternately layered with coke from the top, forming ore and coke layers. High-temperature reducing gases flow upwards along the front of the tuyeres to obtain pig iron. It should be noted that ore raw materials and coke will be collectively referred to as raw materials below. In the diagram, symbol 1 represents the blast furnace, 2 represents the tuyeres, 3 represents the ore layer, 4 represents the coke layer, and 5 represents the molten layer.

[0003] In the operation of such a blast furnace, the flow of gas inside the furnace affects the reduction efficiency of ore-based raw materials and the amount of heat dissipated outside the furnace. Generally, in order to improve the reduction efficiency of ore-based raw materials and reduce the amount of heat dissipated outside the furnace, it is desirable to have more gas flow near the center of the blast furnace.

[0004] The main reasons for this can be summarized in the following two points.

[0005] (1) If the gas flow near the furnace wall of the blast furnace increases, the heat dissipation to the outside of the blast furnace will increase and the energy efficiency will decrease.

[0006] (2) In the lower part of the blast furnace, the ore raw materials charged into the blast furnace are heated and reduced by reducing gas, forming a melting zone. The melting zone is a region where a rock-like structure formed by the melting of ore particles and coke pores exist alternately. The melting layer has a rock-like structure as described above, where ore particles are melted together, so the porosity within the layer is extremely low. On the other hand, the porosity of the coke pores is higher than that of the melting layer. Therefore, in the melting zone, gas flowing in from the vertical direction selectively flows through the coke pores. Here, if the amount of gas flowing near the center of the blast furnace increases, the height region of the melting zone expands. As a result, the number of coke pores in the melting zone increases, and the gas permeability improves.

[0007] To increase the gas flow near the center of the blast furnace, it is effective to place large-diameter raw materials near the center in the radial direction of the blast furnace and small-diameter raw materials near the furnace wall.

[0008] This is because, compared to a layer filled with small-diameter particles, the total specific surface area of ​​the particles filling the large-diameter particle layer is smaller. In other words, the friction between the flowing gas and the particles in the filling layer is reduced, and the gas flow rate increases.

[0009] Therefore, various techniques have been proposed to increase the gas flow near the center of the blast furnace by controlling the particle size distribution and even the layer thickness of the ore and coke layers formed inside the blast furnace.

[0010] For example, Patent Document 1 proposes "a method for charging raw materials into a blast furnace using a hopper and a bell-less charging device, which is a method for charging raw materials into a blast furnace using a bell-less charging device with a rotating chute and a hopper arranged parallel to the top of the furnace, characterized in that..."

[0011] The raw materials are temporarily stored before being loaded into the blast furnace. They are then discharged into the furnace top hopper via a rotary chute located below the blast furnace.

[0012] A freely tilting movable plate is installed inside the aforementioned top hopper, allowing the raw materials loaded into the hopper to collide with it. When the front end of the rotating chute tilts from the periphery towards the center of the blast furnace, the movable plate is operated to align the falling direction of the raw materials with the discharge direction of the top hopper. The falling position of the raw materials loaded into the top hopper is set directly above the discharge outlet. Within the top hopper, due to the accumulation characteristics of the raw materials, fine particles accumulate near the discharge outlet, while coarse particles accumulate further away.

[0013] When the front end of the rotary chute is tilted from the center of the blast furnace outwards, the movable plate is operated to make the direction of the raw material's fall opposite to the discharge port of the top hopper. This causes the raw material loaded into the top hopper to fall onto the side wall away from the discharge port, with coarse particles accumulating near the discharge port and fine particles accumulating away from it.

[0014] This causes coarse particles to accumulate in the center of the blast furnace.

[0015] Existing technical documents

[0016] Patent documents

[0017] Patent Document 1: Japanese Patent No. 4591520 Summary of the Invention

[0018] However, in Figure 2 In the bell-less blast furnace shown, a temporary top silo for storing the raw materials to be loaded into the blast furnace is set up at the top of the furnace. Then, the raw materials discharged from the top silo are opened through the flow regulating valve and loaded into the blast furnace via the collecting hopper and rotary chute. At this time, the position of the front end of the rotary chute in the radial direction is sometimes changed (hereinafter also referred to as tilting) to adjust the falling position of the raw materials in the radial direction of the blast furnace.

[0019] It should be noted that in the diagram, symbol 6 represents the furnace top hopper, 7 represents the flow regulating valve, 8 represents the collecting hopper, and 9 represents the rotary chute.

[0020] That is, when charging raw materials into the blast furnace, the rotary chute rotates around the blast furnace's axis at a certain speed along the circumference of the blast furnace, while simultaneously tilting at certain intervals. There are roughly two types of tilting: the tilting from near the furnace wall towards the center of the blast furnace is called forward tilting charging, and the tilting from the center of the blast furnace towards the furnace wall is called reverse tilting charging.

[0021] Among them, reverse-tilting charging has the effect of suppressing the flow of raw materials into the center of the blast furnace after they are charged and piled up inside. Therefore, compared with forward-tilting charging, the raw material pile shape is easier to stabilize with reverse-tilting charging, which is beneficial for controlling the particle size distribution of raw materials in the blast furnace.

[0022] As described above, from the viewpoint of increasing the gas flow rate near the center of the blast furnace, it is effective to place large-diameter raw materials near the center and small-diameter raw materials near the furnace wall in the radial direction of the blast furnace. In this specification, coke, ore (including lumpy ore), and auxiliary raw materials such as limestone charged from the top of the blast furnace are collectively referred to as raw materials. For all these raw materials, it is most preferable to place large-diameter raw materials in the center of the blast furnace, but it is also effective to place large-diameter raw materials in the center for any one or more of coke, ore, or mixtures of coke and ore. A batch of raw materials is usually stored in the top hopper. Therefore, when performing reverse-tilting charging, it is preferable to have a large particle size distribution of raw materials in the top hopper that discharges a large amount of large-diameter raw materials during the initial stage of raw material discharge.

[0023] In this respect, the technology in Patent Document 1 uses a freely tilting movable plate (hereinafter also referred to as a segregation control plate) installed in the furnace top hopper to intentionally segregate the raw materials stored in the furnace top hopper. Thus, an optimal particle size distribution of the raw materials in the furnace top hopper is achieved according to the tilting method.

[0024] However, the technology in Patent Document 1 cannot fully achieve a suitable particle size distribution of raw materials in the top hopper of the furnace for reverse-tilting charging. That is, sometimes a certain amount of large-diameter raw materials are mixed in with the raw materials discharged in the middle to the end of the discharge of raw materials from the top hopper, which may result in a certain amount of large-diameter raw materials being mixed near the furnace wall.

[0025] The present invention was developed in view of the above-mentioned situation, and aims to provide a method for charging raw materials into a blast furnace, which can achieve a raw material particle size distribution in the furnace top hopper suitable for both forward tilting and reverse tilting charging. Thus, regardless of the tilting method, the gas flow near the center of the blast furnace can be increased, thereby further improving ventilation and reduction efficiency.

[0026] Therefore, the inventors conducted repeated and in-depth research in order to achieve the above objectives.

[0027] First, the inventors investigated why the material particle size distribution in the furnace top hopper, which is suitable for reverse tilting loading, is sometimes not fully realized in the technology of Patent Document 1.

[0028] Typically, from the perspective of miniaturizing the hopper for receiving raw materials discharged from the furnace top silo and from the perspective of enhancing particle size segregation within the silo, such as Figure 3 As shown, the raw material discharge port of the furnace top silo is located on a horizontal plane (projected in the vertical direction), offset from the center of the raw material storage section towards the blast furnace axis. It should be noted that... Figure 3 This is a schematic diagram showing the layout of the various parts of the furnace top silo when viewed from above in a vertical direction. In the diagram, 6-1 is the raw material storage section, and 6-2 is the raw material discharge outlet.

[0029] Here, the eccentric direction refers to the direction from the center of the raw material storage section towards the center of the raw material discharge outlet on the horizontal plane. When viewed from above in the vertical direction, the direction rotated 90° clockwise from the eccentric direction is called the first direction, the direction rotated 180° is called the opposite eccentric direction, and the direction rotated 270° is called the second direction. It should be noted that the raw material discharge outlet of the furnace top silo is eccentrically positioned on the horizontal plane (projected vertically) from the center of the raw material storage section towards the axis of the blast furnace. Therefore, when a furnace top silo is installed at the top of the blast furnace, the eccentric direction is usually the same as the direction from the center of the raw material storage section towards the axis of the blast furnace (hereinafter also referred to as the blast furnace axis direction).

[0030] When performing anti-tilting loading according to the technology of Patent Document 1, such as Figure 4 As shown, the segregation control plate is operated so that the direction of the raw material's fall on the horizontal plane is opposite to the raw material outlet of the furnace top hopper, that is, near the wall portion on the opposite eccentric side (hereinafter also referred to as the eccentric opposite side wall portion). Therefore, the shape of the raw material accumulation layer in the furnace top hopper is such that the raw material accumulation surface slopes downward in the vertical direction from the eccentric direction (from the wall portion on the opposite eccentric side towards the eccentric direction (hereinafter also referred to as the eccentric side wall portion)). In the figure, 6-3 is the segregation control plate.

[0031] In this scenario, the particle size distribution of raw materials within the furnace top silo, and the order in which raw materials are discharged from the silo (the discharge time of each raw material storage location within the furnace top silo), are calculated using a numerical simulation method known as the discrete element method. For example... Figure 5As shown, more than half of the large-diameter raw materials are concentrated near the raw material discharge outlet, which is the area discharged in the initial stage of raw material discharge. However, it was also found that the majority of the remaining large-diameter raw materials are located near the wall sections on the first and second directions (hereinafter also referred to as the first and second wall sections) perpendicular to the eccentric direction of the furnace top hopper, which is the area discharged in the middle to late stages of raw material discharge. That is, it can be seen that if reverse tilting charging is carried out, a certain amount of large-diameter raw materials are also mixed near the furnace wall of the blast furnace.

[0032] Based on this, the inventors conducted further research and found the following to be effective:

[0033] • This ensures that the raw materials loaded into the furnace top hopper fall not only near the eccentric opposite sidewalls, but also near the first and second walls.

[0034] Therefore, as Figure 6 As shown, the shape of the raw material accumulation layer in the furnace top hopper is such that it slopes downward in the vertical direction not only from the eccentric opposite side wall, but also from the first wall and the second wall toward the raw material outlet. In other words, the shape of the raw material accumulation layer is roughly mortar-shaped.

[0035] Moreover, it was discovered that large-diameter raw materials were more densely clustered near the raw material discharge outlet.

[0036] It should be noted that the inventors considered the above reasons as follows.

[0037] That is, compared with small-diameter raw materials, large-diameter raw materials tend to roll more easily on the accumulation surface. Therefore, by dispersing the falling position of the raw materials charged into the furnace top hopper not only near the eccentric opposite sidewalls, but also near the first and second walls, a raw material accumulation layer is formed that slopes vertically downward from the first and second walls toward the raw material discharge port. Then, the gradually added large-diameter raw materials roll on this accumulation surface, while the small-diameter raw materials accumulate at the falling position, thereby making the large-diameter raw materials more densely concentrated near the raw material discharge port.

[0038] Then, based on the above insights, the inventors studied a method to distribute the falling position of the raw material charged into the furnace top hopper not only near the eccentric opposite sidewall, but also near the first and second walls, and found the following to be effective:

[0039] • A structure with a raw material collision surface is installed inside the raw material storage section of the furnace top silo.

[0040] • The shape of the material collision surface is such that it slopes downward from the top of the structure toward the end of the material collision surface in the first direction and the second direction, which are opposite to the eccentricity and perpendicular to the opposite eccentricity and the vertical direction, respectively.

[0041] Furthermore, the inventors and others conducted further and repeated research and discovered that: Figure 8 As shown,

[0042] The shape of the material collision surface is such that, in addition to the eccentric opposite direction and the first and second directions perpendicular to the eccentric opposite direction and the vertical direction, it also slopes downward from the top of the structure toward the end of the material collision surface in the eccentric direction.

[0043] • Based on the tilting method when charging raw materials into the blast furnace, the raw material collision position within the structure (located inside the raw material storage section of the furnace top hopper) is determined, thereby enabling the achievement of suitable raw material particle size distribution within the furnace top hopper for both forward and reverse tilting charging. It should be noted that in the figure, 6-4 represents the structure, and 6-5 represents the raw material collision surface.

[0044] This invention was completed based on the above insights, and further repeated research.

[0045] That is, the main components of the present invention are as follows.

[0046] 1. A method for charging raw materials into a blast furnace,

[0047] The aforementioned blast furnace has a top hopper at the top.

[0048] At least one of the above-mentioned furnace top hoppers has the following features:

[0049] Raw material storage department

[0050] A structure comprising a raw material loading inlet for loading raw materials into the raw material storage section from above, a structure disposed inside the raw material storage section and having a raw material collision surface that collides with the raw materials loaded from the raw material loading inlet, and a structure comprising a raw material loading inlet for loading raw materials into the raw material storage section from above, and a structure comprising a raw material loading inlet for loading raw materials into the raw material storage section from above, and a structure comprising a raw material loading inlet for loading raw materials into the raw material storage section from above, and a structure comprising a raw material collision surface disposed inside the raw material storage section and having a raw material collision surface that collides with the raw materials loaded from the raw material loading inlet, and a structure comprising a raw material loading inlet for loading raw materials into the raw material storage section from above, and a structure comprising ... collision surface that collides with the raw materials loaded from the raw material loading inlet, and a structure comprising a raw material loading inlet for loading raw materials into the raw material storage section from above, and a structure comprising

[0051] The raw materials in the aforementioned raw material storage section are discharged from the raw material discharge port below the aforementioned raw material storage section.

[0052] The aforementioned raw material discharge outlet is located off-center from the center of the aforementioned raw material storage section on a horizontal plane.

[0053] Furthermore, the material collision surface of the aforementioned structure slopes downward from the top of the structure toward the end of the material collision surface, at least in the eccentric direction, the opposite eccentric direction, and in the first and second directions perpendicular to the eccentric direction and the vertical direction.

[0054] Therefore, the above-mentioned method for charging raw materials into the blast furnace includes the following steps:

[0055] In the storage process, the raw material is loaded into the raw material storage section from the raw material loading inlet of the furnace top silo, causing the raw material to collide with the structure, and then the raw material is stored in the raw material storage section.

[0056] In the loading process, the raw materials stored in the raw material storage section are discharged from the raw material discharge outlet, and the discharged raw materials are loaded into the blast furnace through the rotary chute of the blast furnace.

[0057] Based on the tilting method of the loading process described above, the collision position of the raw materials in the structure of the storage process described above is determined.

[0058] Here, the eccentric direction is the direction in which the raw material discharge port is eccentrically located from the center of the raw material storage section on the horizontal plane. Conversely, the opposite eccentric direction is the direction opposite to the eccentric direction on the same horizontal plane.

[0059] 2. According to the raw material charging method of the blast furnace described in 1 above, wherein the inclination angles α and α′ of the line segment connecting the top of the structure and the end of the raw material collision surface in the eccentric direction and the opposite direction of the eccentricity with the horizontal direction are 25 to 45° respectively.

[0060] 3. The raw material charging method for the blast furnace according to 1 or 2 above, wherein the inclination angles β and γ of the line segment connecting the top of the structure and the end of the raw material collision surface in the first direction and the second direction to the horizontal direction are 25 to 45° respectively.

[0061] 4. The raw material charging method for a blast furnace according to any one of 1 to 3 above, wherein the dimensionless distance (r / R) between the top of the structure and the center of the raw material storage section on the horizontal plane is in the range of 0 to 0.6.

[0062] Here, the dimensionless distance (r / R) refers to the value obtained by dividing the distance (r) from the center of the raw material storage section on the horizontal plane by the inner diameter (R) of the raw material storage section.

[0063] According to the present invention, it is possible to achieve a raw material particle size distribution in the furnace top hopper that is suitable for both forward tilting and reverse tilting loading.

[0064] As a result, during blast furnace operation, regardless of the tilting method, the gas flow near the center of the blast furnace can be increased, thereby further improving ventilation and reduction efficiency.

[0065] Furthermore, since the present invention does not require strict control or complex structures, it is also excellent in terms of operability and maintainability. Attached Figure Description

[0066] Figure 1 This is a schematic diagram showing the gas flow inside a blast furnace.

[0067] Figure 2 This is a schematic diagram showing the procedure for loading raw materials into a blast furnace.

[0068] Figure 3 This is a schematic diagram showing the layout of the various parts of the furnace top silo when viewed from above in a vertical direction.

[0069] Figure 4 This is a schematic diagram showing the accumulation of raw materials in the furnace top silo when raw materials are loaded into the furnace top silo equipped with a segregation control plate (assuming reverse tilting loading). (a) is a schematic diagram viewed from the eccentric direction, and (b) is a three-dimensional view.

[0070] Figure 5 The results are numerical simulations of the particle size distribution of raw materials in the furnace top silo (assuming reverse tilting loading) when raw materials are loaded into the furnace top silo equipped with a segregation control plate, and the discharge sequence of raw materials when they are discharged from the furnace top silo (discharge time of each raw material storage location in the furnace top silo).

[0071] Figure 6 This is a schematic diagram showing the preferred material accumulation in the furnace top hopper during reverse tilting loading. (a) is a schematic diagram viewed from an eccentric direction, and (b) is a three-dimensional view.

[0072] Figure 7 This is a schematic diagram showing the preferred material accumulation in the furnace top hopper during positive tilting loading. (a) is a schematic diagram viewed from an eccentric direction, and (b) is a three-dimensional view.

[0073] Figure 8 This is a schematic diagram illustrating an example of a method for storing raw materials in a blast furnace top silo using a raw material charging method according to one embodiment of the present invention.

[0074] Figure 9 This is a schematic diagram showing an example of the shape (outer periphery) from the top of the structure to the end of the material collision surface.

[0075] Figure 10 A schematic diagram showing an example of a structure installed inside a furnace top silo.

[0076] Figure 11 A schematic diagram showing the preferred area located at the top of the structure.

[0077] Figure 12 Regarding conditions 1 and 2, assuming reverse tilting loading, the numerical simulation results are as follows: the particle size distribution of raw materials in the furnace top silo when raw materials are loaded into the furnace top silo, and the raw material discharge sequence (discharge time of each raw material storage location in the furnace top silo) when raw materials are discharged from the furnace top silo.

[0078] Figure 13 This is a schematic diagram of the apparatus used in the model experiment.

[0079] Figure 14 This is a schematic diagram showing the particle size distribution of the raw material obtained through model experiments (positive tilting loading).

[0080] Figure 15 This is a schematic diagram showing the particle size distribution of the raw material obtained through model experiments (reverse tilting loading).

[0081] Figure 16 This is a schematic diagram illustrating the key points of adjusting the collision position of raw materials in the structure. Detailed Implementation

[0082] The present invention will be described based on the following embodiments.

[0083] One embodiment of the present invention relates to a blast furnace raw material charging method carried out in a blast furnace with one or more top silos provided at the top, comprising the following steps:

[0084] In the storage process, raw materials are loaded into the raw material loading inlet of the furnace top silo, causing the raw materials to collide with a structure of a specified shape, and then the raw materials are stored in the raw material storage section of the furnace top silo.

[0085] In the loading process, the raw materials stored in the raw material storage section of the furnace top silo are discharged and loaded into the blast furnace through the rotary chute of the blast furnace.

[0086] Here, as Figure 2 As shown, the top silo is located at the top of the blast furnace and is used to temporarily store the raw materials charged into the blast furnace. There is no particular limit to the number of top silos located at the top of the blast furnace; the number can be appropriately set according to the type and quantity of raw materials and the required volume of the top silos, usually 2 to 4.

[0087] The following describes the furnace top hopper used in the blast furnace raw material charging method according to one embodiment of the present invention, as well as the storage and charging steps of the blast furnace raw material charging method according to one embodiment of the present invention.

[0088] [Furnace Top Charge Bin]

[0089] In one embodiment of the present invention, a method for charging raw materials into a blast furnace includes at least one material in the top hopper that uses, as described above... Figure 8 The furnace top hopper shown has the following features:

[0090] Raw material storage department

[0091] The raw materials are loaded into the raw material loading inlet (not shown) of the raw material storage section from above.

[0092] A structure disposed inside the raw material storage section and having a raw material collision surface for colliding with the raw material loaded from the raw material loading inlet, and

[0093] The raw materials in the raw material storage section are discharged to the raw material discharge outlet below the raw material storage section.

[0094] Preferably, the furnace top silos located at the top of the blast furnace are all the above-mentioned furnace top silos.

[0095] It should be noted that the terms "above," "below," "upper part," and "lower part," unless otherwise specified, refer to the vertical direction of "above," "below," "upper part," and "lower part."

[0096] Here, the raw material inlet is located above the raw material storage section. The position of the raw material inlet on the horizontal plane is not particularly limited, but it is generally located closer to the blast furnace axis than the center of the raw material storage section (in the same direction as the raw material outlet).

[0097] Furthermore, when the raw materials loaded through the raw material loading inlet collide with the raw material collision surface of the structure located inside the raw material storage section, they fall into the raw material storage section and are temporarily stored there. It should be noted that the raw materials temporarily stored in the raw material storage section are usually in batches. In addition, the raw material storage section has a main body in the shape of a cylinder, a truncated cone, or a combination thereof, and a diameter-reducing section that tapers downwards.

[0098] It should be noted that the maximum diameter (outer diameter) of the furnace top hopper is usually around 4000-5000 mm, and the height of the furnace top hopper is around 9000-13000 mm.

[0099] Next, as the blast furnace is running, the flow regulating gate is opened, and the raw materials are gradually discharged from the raw material outlet at the lower end of the narrowed section of the raw material storage section by their own weight. The raw materials are then loaded into the blast furnace through the collecting hopper and the rotary chute.

[0100] like Figure 3 As shown, the raw material discharge port is eccentrically located from the center of the raw material storage section in the horizontal plane. Typically, the center-to-center distance (eccentricity) between the raw material storage section and the raw material discharge port in the horizontal direction, A, is 0.60 to 0.70 times the inner diameter R of the raw material storage section. Furthermore, the inner diameter B of the raw material discharge port is typically 0.10 to 0.30 times the inner diameter R of the raw material storage section. It should be noted that the center position and inner diameter of the raw material storage section are based on the installation height at the top of the structure described later. Additionally, the center position and inner diameter of the raw material discharge port are based on the height at which it connects to the lower end of the raw material storage section. The same applies thereafter.

[0101] It should be explained that Figure 3The example given is a circular horizontal cross-section of the raw material storage section. In other cases, the center of the raw material storage section is set as the centroid of the horizontal cross-section with the largest area. In this case, the eccentric direction is the direction from the center of the raw material storage section toward the center of the raw material discharge outlet on the horizontal cross-section (the horizontal cross-section with the largest area), where R is half the length of the raw material storage section in the eccentric direction of the horizontal cross-section.

[0102] Furthermore, in a blast furnace raw material charging method according to one embodiment of the present invention, the shape of the raw material collision surface of the above-mentioned structure is extremely important.

[0103] Specifically, the important thing is as follows Figure 8 The shape of the material collision surface shown is inclined downward from the top of the structure (material collision surface) toward the end of the material collision surface, at least in the eccentric direction, the opposite eccentric direction, the first direction perpendicular to the eccentric direction and the vertical direction, and the second direction.

[0104] That is, as described above, during the anti-dumping loading, such as Figure 6 As shown, the falling position of the raw material loaded into the furnace top hopper is not only distributed near the eccentric opposite sidewalls, but also near the first and second walls. Therefore, it is important that the shape of the raw material accumulation layer within the furnace top hopper slopes downwards vertically not only from the eccentric opposite sidewalls, but also from the first and second walls towards the raw material discharge outlet; in other words, the shape of the raw material accumulation layer is approximately mortar-shaped. This results in a more dense accumulation of large-diameter raw materials near the raw material discharge outlet. Therefore, it is important that the shape of the raw material collision surface (the outer perimeter of the vertical section) of the aforementioned structure slopes downwards not only in the eccentric opposite direction, but also in the first and second directions respectively, from the top of the structure towards the end of the raw material collision surface.

[0105] Additionally, in the case of positive tilting loading, such as Figure 7 As shown, the falling positions of the raw materials loaded into the furnace top hopper are not only distributed near the eccentric sidewall (i.e., near the raw material discharge port), but also near the first and second walls. Therefore, it is important that the shape of the raw material accumulation layer within the furnace top hopper slopes downwards vertically not only from the eccentric sidewall, but also from the first and second walls towards the opposite eccentric sidewall. This causes large-diameter raw materials to accumulate away from the raw material discharge port. That is, large-diameter raw materials are discharged at the end of the furnace top hopper's discharge process. Therefore, it is important that the shape of the raw material collision surface (the outer perimeter of the vertical section) of the aforementioned structure also slopes downwards in the eccentric direction from the top of the structure towards the end of the raw material collision surface.

[0106] Here, in the eccentric direction and the opposite direction of eccentricity, the downward inclination from the top of the structure toward the end of the material collision surface means, as... Figure 8 As shown, when viewing the vertical section of the structure passing through the top of the structure from the first direction, it means sloping downwards from the top of the structure towards the end of the material collision surface. Similarly, sloping downwards from the top of the structure towards the end of the material collision surface in both the first and second directions means, as... Figure 8 As shown, when viewing the vertical section of the structure passing through the top of the structure from the bias direction, it means that the structure slopes downward from the top towards the end of the material collision surface in the first and second directions. Alternatively, it means that on the section of the structure along the first and second directions, the structure slopes downward from the highest point of the material collision surface towards the end.

[0107] It should be noted that the material collision surface is on top of the structure (the area of ​​the structure when viewed from above). Therefore, the top of the structure is the highest point in the vertical direction of the material collision surface. Here, when there are multiple highest points on the material collision surface, the point furthest from the material discharge outlet in the eccentric direction is considered the top. Furthermore, components used to fix the structure are also discharged outside the material collision surface. It should be noted that the material collision surface can consist of a single continuous surface or multiple surfaces.

[0108] Furthermore, the inclination angles α and α′ of the line segments connecting the top of the structure and the end of the material collision surface in the eccentric direction and the opposite eccentric direction to the horizontal direction are preferably 25 to 45°, respectively. α and α′ are more preferably 40 to 43°, respectively.

[0109] Furthermore, the inclination angles β and γ of the line segments connecting the top of the structure and the end of the material collision surface in the first and second directions with the horizontal direction are preferably 25 to 45°, respectively. β and γ are more preferably 40 to 43°, respectively.

[0110] Similarly, it is also preferable that the shape from the top of the structure to the end of the material collision surface in the direction between the first direction and the opposite eccentric direction to the second direction (a direction between 90° and 270° clockwise from the eccentric direction) slopes downward from the top of the structure toward the end of the material collision surface. The preferred inclination angles of the line segments connecting the top of the structure and the end of the material collision surface in these directions are also the same as the inclination angles α, α′, β, and γ described above in the horizontal direction.

[0111] It should be noted that the shape (outer perimeter shape) of each vertical section of the structure from the top of the structure to the end of the material collision surface does not need to be a constant inclination in any direction; it can be a shape with varying inclination, for example, as... Figure 9 As shown, it has an arc-shaped form with a gradually changing inclination.

[0112] Furthermore, the shape of the structure from the top to the end of the material collision surface in the direction between the first direction, the eccentric direction, and the second direction (the direction between 0° and 90° clockwise from the eccentric direction, and between 270° and 360° clockwise, but excluding the first and second directions) is not particularly limited.

[0113] For example, in the opposite direction to the eccentricity, and in the same direction as the first and second directions, the structure can be inclined downwards from the top toward the end of the material collision surface. In this case, the shape of the structure is, for example, as... Figure 10 As shown, shapes include conical or oblique conical shapes, elliptical cones, shapes with a cone attached to the upper part of a truncated cone (shape 1), shapes formed by bisecting a cone and bisecting an elliptical cone and attaching them to each other at the cut surface (shape 2), dome shapes with a spherical material collision surface, and polyhedral shapes such as square pyramids, hexagonal pyramids, and octagonal pyramids, which are formed by cutting these shapes at any position along the vertical direction. It should be noted that the interior of the structure can be hollow, or no components can be placed on the surfaces other than the material collision surface, such as the bottom and side surfaces. In addition, as long as the area of ​​the material collision surface does not change, the above-mentioned shapes also include shapes that vary by placing components on the bottom surface, etc.

[0114] Furthermore, the length 'a' of the aforementioned structure (the distance between the ends of the raw material collision surfaces in the horizontal direction when the structure is viewed from the first direction) is preferably 0.4 to 0.8 times the inner diameter R of the raw material storage section (reference). Figure 8 (The width and height of the structure described later are the same). The width of the structure (the distance between the ends of the material collision surfaces in the horizontal direction when the structure is viewed from the eccentric direction) b is preferably 0.4 to 0.8 times the inner diameter of the material storage section R. The height of the structure (the distance from the lower end of the material collision surface to the top) is preferably 0.47 to 1.0 times the length of the structure a.

[0115] It should be noted that the shape of the structure can be symmetrical in the first and second directions, or it can be asymmetrical.

[0116] Furthermore, regarding the horizontal placement of the aforementioned structure, as follows: Figure 11 As shown, the top of the structure is preferably located in the range of 0 to 0.6 in dimensionless distance (r / R) from the center of the raw material storage section.

[0117] Here, the dimensionless distance (r / R) is the value obtained by dividing the distance (r) from the center of the raw material storage section on the horizontal plane (projected onto the vertical direction) by the inner diameter (R) of the raw material storage section.

[0118] Furthermore, there are no particular limitations on the vertical placement of the aforementioned structure, but the dimensionless height (h′ / H) of the top of the structure is preferably in the range of 0.75 to 0.85.

[0119] Here, the dimensionless height (h′ / H) refers to the vertical distance (height) from the bottom of the furnace top silo (the height of the raw material outlet) to the top of the structure: h′ divided by the height of the furnace top silo: H.

[0120] Furthermore, the aforementioned structure is preferably arranged symmetrically from left to right, with a vertical line passing through the center of the raw material storage section as a reference when viewed from an eccentric direction. However, it may not be symmetrical from left to right if it is inclined downwards from the top of the structure toward the ends in the first and second directions.

[0121] Furthermore, there are no particular limitations on the material of the aforementioned structure; ordinary steel or similar materials can be used. Additionally, there are no particular limitations on the method of installing the structure. For example, the beam component can be fixed to the inner wall of the furnace top hopper using metal parts and welding, and then the aforementioned structure can be fixed to this beam component using metal parts and welding. Furthermore, the aforementioned structure may also include a position adjustment mechanism for changing its position and an angle adjustment mechanism for changing its installation angle.

[0122] [Storage Process]

[0123] One embodiment of the present invention relates to a blast furnace raw material charging method, the storage step of which involves loading the raw material from the raw material loading inlet of the furnace top silo into the raw material storage section, causing the raw material to collide with the structure, and then storing the raw material in the raw material storage section.

[0124] Moreover, it is important to determine (set) the collision position of the raw materials in the structure in this process according to the tilting method used in the loading process described later.

[0125] As described above, the preferred particle size distribution of the raw material in the furnace top hopper varies depending on the tilting method. For example, when loading via reverse tilting, such as... Figure 6 As shown, it is important that the shape of the raw material accumulation layer in the furnace top hopper slopes downwards vertically not only from the eccentric opposite sidewall, but also from the first and second walls toward the raw material discharge outlet. In other words, the shape of the raw material accumulation layer is roughly mortar-shaped (large-diameter raw materials accumulate near the raw material discharge outlet). Therefore, in the case of reverse tilting loading, the raw material collision point in the structure is located on the eccentric opposite side of the top of the structure.

[0126] On the other hand, when loading with a tilting motion, such as Figure 7As shown, it is important that the shape of the raw material accumulation layer in the furnace top hopper slopes downwards in the vertical direction not only from the eccentric sidewall, but also from the first and second walls toward the opposite eccentric sidewall. Therefore, in the case of positive tilting loading, the raw material collision point in the structure is located on the eccentric side of the top of the structure.

[0127] Here, the collision position of the raw materials in the structure is determined based on the representative position in the opposite direction of the eccentricity of the collision range of the raw materials in the structure, and is determined to be either the opposite direction of the eccentricity or the eccentric direction.

[0128] That is, with the top of the structure as the origin, the distance from the top of the structure in the opposite direction of eccentricity as the horizontal axis (X-axis), and the distance from the top of the structure in the first direction as the vertical axis (Y-axis) (distances to the opposite direction of eccentricity and the first direction are positive values, and distances to the eccentric direction and the second direction are negative values), a graph is plotted showing the collision positions (ranges) of each particle of the raw material in the structure (raw material collision surface) as viewed from above in the vertical direction. Then, the average value of the centroid position in the opposite direction of eccentricity, i.e., the collision position of each particle in the graph of the opposite direction of eccentricity (X-coordinate), is taken as the representative position of the raw material collision range in the opposite direction of eccentricity in the structure (hereinafter simply referred to as the representative position in the opposite direction of eccentricity). Similarly, the average value of the centroid position in the first direction of eccentricity, i.e., the collision position of each particle in the graph of the first direction (Y-coordinate), is taken as the representative position of the raw material collision range in the first direction of eccentricity in the structure (hereinafter also simply referred to as the representative position in the first direction).

[0129] For example, if the collision position in the opposite eccentric direction is a positive value (greater than 0), the collision position of the raw material in the structure is on the opposite eccentric side of the top of the structure. If the collision position in the opposite eccentric direction is a negative value (less than 0), the collision position of the raw material in the structure is on the opposite eccentric side of the top of the structure.

[0130] It should be noted that, in the case of reverse tilting loading, the preferred collision representative position in the opposite eccentric direction is within the range of a1 / 4 to a1 / 2. Here, a1 is the distance between the top of the structure and the end of the material collision surface in the opposite eccentric direction (the distance between the top of the structure and the end of the material collision surface in the opposite eccentric direction when viewing the structure from the first direction, see reference). Figure 8 ).

[0131] Furthermore, in the case of positive tilting loading, it is preferable that the collision representative position in the opposite eccentric direction is in the range of -a2 / 2 to -a2 / 4. Here, a2 is the distance between the top of the structure and the end of the material collision surface in the eccentric direction (the distance between the top of the structure and the end of the material collision surface in the eccentric direction when viewing the structure from the first direction, see reference). Figure 8 ).

[0132] It should be noted that the collision range of the raw materials in the structure in the first direction is not particularly limited, but it is preferred that the representative position of the collision range of the raw materials in the structure in the first direction (hereinafter also referred to as the collision representative position in the first direction) is in the range of -b / 10 to b / 10. It is particularly preferred that the collision representative position in the first direction is 0.

[0133] Furthermore, the collision position of the raw materials within the structure is adjusted so that at least 80%, preferably at least 90%, of the raw material particles falling from the raw material loading inlet collides with the structure (raw material collision surface). (That is, the collision ratio between the structure and the raw materials (= [number of raw materials colliding with the structure (raw material collision surface)] / [number of raw materials loaded into the furnace top hopper] × 100) is at least 80%, preferably at least 90%. The collision ratio between the structure and the raw materials can also be 100%.

[0134] It should be noted that the collision location and angle of the raw materials within the structure can be determined, for example, by... Figure 16 A movable control panel 17 is installed in the raw material passage from the receiving hopper to the raw material loading inlet of the furnace top silo, as shown. Its position and angle can be adjusted. It should be noted that... Figure 16 An example is shown where the raw material collision surface of the movable control plate 17 is fixed perpendicular to the horizontal plane, allowing the movable control plate 17 to move along the eccentric direction of the furnace top hopper 6 in the opposite direction to the eccentricity, but this is not the only example. For instance, by changing the angle of the raw material collision surface of the movable control plate 17, its position and angle can be changed, thereby enabling more precise adjustment of the raw material collision position and collision angle within the structure.

[0135] [Loading process]

[0136] In the above-mentioned storage process, the raw materials stored in the raw material storage section of the furnace top silo are discharged from the raw material discharge port. The discharged raw materials are then loaded into the blast furnace via the rotary chute through either reverse tilting or forward tilting.

[0137] That is, in the case of reverse tilting charging, the raw material is discharged from the furnace top silo, which is suitable for the particle size distribution of the raw material for reverse tilting charging, and the discharged raw material is loaded into the blast furnace.

[0138] On the other hand, in the case of forward tilting charging, the raw material is discharged from the furnace top silo, which is suitable for the particle size distribution of the raw material for forward tilting charging, and then the discharged raw material is charged into the blast furnace.

[0139] As a result, both forward tilting and reverse tilting charging increase the gas flow rate near the center of the blast furnace, improving ventilation and reduction efficiency.

[0140] There are no other specific restrictions besides those mentioned above. The standard method will suffice.

[0141] Example

[0142] The furnace top silo is modeled according to the following conditions 1 and 2. The discrete element method is used to calculate the particle size distribution of the raw materials in the furnace top silo when the raw materials are loaded into the furnace top silo, and the raw material discharge sequence when the raw materials are discharged from the furnace top silo (discharge time of each raw material storage location in the furnace top silo).

[0143] • Condition 1 (Example of the invention)

[0144] [The shape of the structure installed inside the furnace top hopper]

[0145] Tilt angle: α=42°, α′=42°, β=42°, γ=42°

[0146] Width: a = R × 0.5, Length: b = R × 0.5, Height: h = a × 0.5

[0147] [Location of structures within the furnace top hopper]

[0148] The top of the structure is located at a position r / R = 0.53 from the center of the raw material storage section along an eccentric direction.

[0149] The height of the top of the structure is set as follows: h′ / H=0.82

[0150] [Places of raw material collision within the structure of the furnace top hopper]

[0151] • When loading with tilting

[0152] Eccentric direction side

[0153] (Collapse position in opposite eccentric directions: -a2 / 4; Collision position in the first direction: 0; Material collision ratio: 100%)

[0154] • Anti-dip loading

[0155] Eccentric opposite direction side

[0156] (The collision position in the opposite direction of the eccentricity is represented by a1 / 2; the collision position in the first direction is represented by 0; the material collision ratio is 100%)

[0157] • Condition 2 (Comparative Example)

[0158] [The shape of the structure installed inside the furnace top hopper]

[0159] Plate-shaped (the segregation control plate mentioned in Patent Document 1)

[0160] Tilt angle:

[0161] • When loading with a tilting motion, α = 80°, β = 0°, γ = 0°

[0162] • When anti-dip loading, α = 155° (α′ = 25°), β = 0°, γ = 0°

[0163] Width: R×0.31, Length: R×1.0, Thickness: 160mm

[0164] [Location of structures within the furnace top hopper]

[0165] The center position of the segregation control plate: located at a position r / R = 0.37 along the eccentric direction from the center of the raw material storage section.

[0166] The center position of the segregation control panel is set at a height of h′ / H = 0.42.

[0167] [Places of raw material collision within the structure of the furnace top hopper]

[0168] Approximate center position of the segregation control plate; raw material collision ratio: 100%.

[0169] (The loading process is the same for both forward and reverse tilting.)

[0170] In addition, the structures in conditions 1 and 2 are arranged symmetrically from left to right with a vertical line passing through the center of the raw material storage section as a reference when viewed from an eccentric direction.

[0171] In addition, the shapes of the raw material storage section, raw material loading inlet, and raw material discharge outlet of the furnace top silo are modeled based on the actual machine under the same conditions as conditions 1 and 2 (R = 2350 mm, H = 12000 mm, center distance between the raw material storage section and the raw material discharge outlet (eccentricity): A = R × 0.64, inner diameter of the raw material discharge outlet: B = R × 0.35).

[0172] Furthermore, the raw material loading conditions are the same as in conditions 1 and 2. Specifically, the raw material mentioned here refers to ore, and the loading amount is equivalent to one batch. Additionally, based on the actual particle size distribution of the raw material, represented by three types of particles—large, medium, and small—the particle size ratio of large, medium, and small particles is set to 3.8:2.0:1.0. Moreover, large, medium, and small particles each contain the same mass. In this case, the coke is loaded using the same hopper in both conditions 1 and 2, and the loading conditions are also identical.

[0173] The average result during anti-dumping loading is used as a substitute. Figure 12 .

[0174] like Figure 12As shown, in condition 1 (inventive example), a raw material particle size distribution suitable for reverse-tilting charging within the furnace top hopper can be achieved. That is, during reverse-tilting charging, large particles accumulate near the raw material discharge outlet, and many large particles can be discharged during the initial stage of discharge from the furnace top hopper. Alternatively, a raw material particle size distribution suitable for forward-tilting charging within the furnace top hopper can also be achieved. That is, during forward-tilting charging, large particles accumulate at a location far from the raw material discharge outlet, and many large particles can be discharged during the final stage of discharge from the furnace top hopper.

[0175] On the other hand, in condition 2 (comparative example), during reverse tilting charging, large particles cannot be sufficiently aggregated near the raw material discharge outlet, making it impossible to achieve a suitable raw material particle size distribution in the furnace top hopper for reverse tilting charging.

[0176] It should be noted that, based on the conditions of Condition 1 (Example of the Invention), even when the shape of the structure varies within the ranges of α = 25–45°, β = 25–45°, and γ = 25–45°, the result is essentially the same as that of Condition 1 (Example of the Invention). Furthermore, even when the position of the top of the structure varies within the range of r / R = 0–0.6, the result is essentially the same as that of Condition 1 (Example of the Invention). Moreover, even when the shape of the structure is other than the aforementioned oblique conical or elliptical conical shapes, the result is essentially the same as that of Condition 1 (Example of the Invention).

[0177] In addition, model experiments were conducted to verify the accuracy of the particle size distribution in the furnace top silo through the above numerical simulation.

[0178] That is, such as Figure 13 As shown, 1 / 17.8 scale models of the furnace top hopper were fabricated to correspond to conditions 1 (inventive example) and 2 (comparative example). In the figures, symbol 10 represents the loading conveyor belt, 11 represents the furnace top hopper model, 12 represents the collecting hopper model, 13 represents the sampling box, 14 represents the roller conveyor belt, 15 represents the conveyor belt for the sampling box, and 16 represents the segregation control plate model or structural model.

[0179] Then, the raw material (here, ore) is loaded into the furnace top silo model via a loading conveyor belt. It should be noted that the loading position of the raw material (the collision position of the raw material in the segregation control plate model and the structural model) is adjusted by changing the position of the loading conveyor belt. After loading, the valve of the discharge port connected to the lower end of the furnace top silo model is opened, and the raw material is discharged from the discharge port. Then, the discharged raw material is collected using multiple sampling boxes. At this time, the sampling boxes are gradually moved horizontally by a conveyor belt, and the discharged raw material is classified sequentially at certain time intervals from the start to the end of discharge. Next, the raw material collected in each sampling box is sieved, the average particle size of the raw material collected in each sampling box is calculated, and then divided by the average particle size of all raw materials before being loaded into the furnace top silo model to calculate the dimensionless particle size of the raw material at each dimensionless discharge time. The results are shown below. Figure 14 and Figure 15 .

[0180] according to Figure 14 and Figure 15 Data supporting the above numerical simulation results were also obtained in the model experiment.

[0181] That is, in condition 1 (inventive example), when the charge is tilted forward, many large particles are discharged at the end of the discharge process from the top hopper. Conversely, when the charge is tilted backward, many large particles are discharged at the beginning of the discharge process from the top hopper.

[0182] On the other hand, in condition 2 (comparative example), when the reverse tilting is used for loading, compared with condition 1 (inventive example), many large particles cannot be discharged in the initial stage of discharge from the furnace top hopper.

[0183] Explanation of reference numerals in the attached figures

[0184] 1: Blast Furnace

[0185] 2: Opportunity

[0186] 3: Ore layer

[0187] 4: Coke layer

[0188] 5: Melting layer

[0189] 6: Furnace top hopper

[0190] 6-1: Raw Material Storage Department

[0191] 6-2: Raw material discharge outlet

[0192] 6-3: Segregation Control Board

[0193] 6-4: Structure

[0194] 6-5: Raw material collision surface

[0195] 6-6: Dispersion Adjustment Plate

[0196] 7: Flow regulating gate

[0197] 8: Collection hopper

[0198] 9: Rotary chute

[0199] 10: Load onto the conveyor belt

[0200] 11: Furnace top silo model

[0201] 12: Collector Hopper Model

[0202] 13: Sampling box

[0203] 14: Roller conveyor belt

[0204] 15: Conveyor belt for sampling boxes

[0205] 16: Segregation control plate model or structural model

[0206] 17: Movable control panel.

Claims

1. A raw material charging method for a blast furnace, the blast furnace having a top bin at a top portion of the blast furnace, at least one of the top bins having: a raw material storage portion, a raw material charging port for charging raw material into the raw material storage portion from above the raw material storage portion, a structure provided inside the raw material storage portion and having a raw material collision surface on which raw material charged from the raw material charging port collides, and a raw material discharge port for discharging raw material in the raw material storage portion to below the raw material storage portion; the raw material discharge port being provided eccentrically from the center of the raw material storage portion in a horizontal plane, in addition, the raw material collision surface of the structure is inclined downward from the top of the structure toward the end of the raw material collision surface in at least an eccentric direction, an opposite eccentric direction, and first and second directions perpendicular to the eccentric direction and a vertical direction, respectively, and the raw material charging method for the blast furnace includes the following steps: a storage step of charging raw material into the raw material storage portion from the raw material charging port of the top bin, causing the raw material to collide with the structure, and then storing the raw material in the raw material storage portion, a charging step of discharging raw material stored in the raw material storage portion from the raw material discharge port, and charging the discharged raw material into the blast furnace via a rotary chute of the blast furnace, in the case where the inclination mode of the charging step is reverse inclination charging, the raw material collision position in the structure of the storage step is on the opposite eccentric direction side with respect to the top of the structure, in the case where the inclination mode of the charging step is normal inclination charging, the raw material collision position in the structure of the storage step is on the eccentric direction side with respect to the top of the structure, here, the eccentric direction is a direction in which the raw material discharge port is eccentric from the center of the raw material storage portion in a horizontal plane, and the opposite eccentric direction is a direction opposite to the eccentric direction in the same horizontal plane.

2. The raw material charging method of a blast furnace according to claim 1, wherein the inclination angles a and a' of line segments connecting the top of the structure and the end of the raw material collision surface in the eccentric direction and the opposite eccentric direction with respect to the horizontal direction are 25 to 45°, respectively.

3. The raw material charging method of a blast furnace according to claim 1 or 2, wherein, the inclination angles β and γ of line segments connecting the top of the structure and the end of the raw material collision surface in the first and second directions with respect to the horizontal direction are 25 to 45°, respectively.

4. The raw material charging method of a blast furnace according to claim 1 or 2, wherein, the dimensionless distance r / R of the top of the structure from the center of the raw material storage portion in a horizontal plane is in the range of 0 to 0.6, here, the dimensionless distance r / R is a value obtained by dividing the distance r from the center of the raw material storage portion in a horizontal plane by the inner diameter R of the raw material storage portion.

5. The raw material charging method of a blast furnace according to claim 3, wherein the dimensionless distance r / R of the top of the structure from the center of the raw material storage portion in a horizontal plane is in the range of 0 to 0.6, here, the dimensionless distance r / R is a value obtained by dividing the distance r from the center of the raw material storage portion in a horizontal plane by the inner diameter R of the raw material storage portion.

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